Updating a Cache Object in C#

I have a cache object in C# that still has not expired yet, and I want to update the value of its key. How do I do that? This is for an ASP.NET MVC web app.  For example:

UserLogin userLogin = new UserLogin() {
  LoginAttempts = 1,
  DateTimeAttempted = DateTime.Now
};

if (System.Web.HttpContext.Current.Cache["LoginInfo"] == null)
{
   System.Web.HttpContext.Current.Cache.Insert("LoginInfo", userLogin, null, DateTime.Now.AddSeconds(60), TimeSpan.Zero);
}

if (System.Web.HttpContext.Current.Cache["LoginInfo"] != null && UserAuthenticationFailedAgain)
{
   userLogin.LoginAttempts = 2;
   userLogin.DateTimeAttempted = DateTime.Now;
   // Now how do I update the value of this existing cache object's key "LoginInfo" so that the when I access Cache["LoginInfo"].LoginAttempts and Cache["LoginInfo"]. DateTimeAttempted, I get 2 and an updated date time, respectively??  I don't see System.Web.HttpContext.Current.Cache.Update() in docs.microsoft.com
}


Many thanks in advance.